Executive Summary

Informations
Name CVE-2021-3656 First vendor Publication 2022-03-04
Vendor Cve Last vendor Modification 2022-03-10

Security-Database Scoring CVSS v3

Cvss vector : CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Overall CVSS Score 8.8
Base Score 8.8 Environmental Score 8.8
impact SubScore 6 Temporal Score 8.8
Exploitabality Sub Score 2
 
Attack Vector Local Attack Complexity Low
Privileges Required Low User Interaction None
Scope Changed Confidentiality Impact High
Integrity Impact High Availability Impact High
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:L/AC:L/Au:N/C:C/I:C/A:C)
Cvss Base Score 7.2 Attack Range Local
Cvss Impact Score 10 Attack Complexity Low
Cvss Expoit Score 3.9 Authentication None Required
Calculate full CVSS 2.0 Vectors scores

Detail

A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "virt_ext" field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.

Original Source

Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3656

CPE : Common Platform Enumeration

TypeDescriptionCount
Application 6
Application 1
Os 2
Os 3415
Os 1
Os 1
Os 3
Os 2
Os 3
Os 1
Os 2
Os 3
Os 2
Os 2
Os 2
Os 2
Os 1
Os 1
Os 4
Os 4
Os 4
Os 5
Os 1

Sources (Detail)

Source Url
MISC https://bugzilla.redhat.com/show_bug.cgi?id=1983988
https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=c7dfa4009965a9b2d7...
https://github.com/torvalds/linux/commit/c7dfa4009965a9b2d7b329ee970eb8da0d32...
https://www.openwall.com/lists/oss-security/2021/08/16/1

Alert History

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Date Informations
2022-03-11 00:22:59
  • Multiple Updates
2022-03-10 21:22:55
  • Multiple Updates
2022-03-05 09:22:53
  • Multiple Updates
2022-03-05 00:22:57
  • First insertion